Exposure to Lead Found To Cause Long-Term Disabilities

Young adults who were exposed to low levels of lead during childhood
may exhibit long-term, perhaps even permanent, developmental and
learning disabilities, a new study has concluded.

A follow-up study of young adults first examined in the early 1970's
found a correlation between the amount of lead exposure a person
experienced as a child and his likelihood of graduating from high
school or having a learning disability.

Although previous studies have shown that children who were exposed
to lead have lower iq's and perform more poorly in school than children
who were not exposed, the authors say this is the first study to show
that these effects persist through young adulthood.

"This study tells us for the first time that the effects of
low-level lead exposure on children are permanent and that they have a
profound effect into adulthood," said the study's chief investigator,
Dr. Herbert Needleman, professor of psychiatry and associate professor
of pediatrics at the University of Pittsburgh.

The federal Agency for Toxic Substances and Disease Registry
estimates that between 3 and 4 million children, or 16 percent of all
children nationwide, have lead blood levels that could be harmful.

Children typically are exposed to lead from lead-based paints,
gasoline, and drinking water. Young children and fetuses have been
shown to be especially susceptible to even minute amounts of lead. Over
the past 10 years, the federal government has continued to lower the
limit of lead in blood it believes to be harmful.

The U.S. Centers for Disease Con8trol recommends that all children
between the ages of 1 and 5 years have a blood test for lead.

An 'Enduring Effect'

In the study, the researchers re-examined 132 of 270 young adults
who had been exposed to lead as children in Chelsea and Sommerville,
Mass., and had been studied by the team since the early 1970's.

In the initial study, the group determined the child's exposure to
lead by measuring the lead content of shed baby teeth.

They found that children who had higher levels of lead in their
teeth--at least 20 parts per million--were more likely to score poorly
on a battery of intelligence and behavioral tests when they attended
elementary school than were children exposed to lower amounts.

The current study, published in the Jan. 11 issue of the The New
England Journal of Medicine, found that 11 years later, young adults
who had been exposed to greater amounts of lead--but who had exhibited
no signs of lead poisoning--still lagged behind their less-exposed
peers.

The young adults who were exposed to higher amounts of lead as
children were seven times less likely to be high-school graduates, and
six times more likely to read at least two years below grade level,
than the less-exposed people their age.

They were also more likely to be absent from school, have longer
reaction times, and poorer eye-hand coordination.

The researchers also found that young adults who had been diagnosed
as having lead poisoning as children were even less likely to be
graduates or to read at their grade level than other members of the
study group.

The study concluded that "exposure to lead, even in children who
remain asymptomatic, may have an important and enduring effect on the
success in life of such children."

And because lead exposure is so widespread, it said, "the
implications of these findings for attempts to prevent school failure
is intriguing."

"I think it's an easy inference that a considerable proportion of
school failures are lead-related," Dr. Needleman said in an interview.
"It's the easiest source of preventable school failure."

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